KABUL, Afghanistan (CNN) -- Taliban militants opened fire at a military ceremony in the capital Sunday morning. A lawmaker, tribal leader and 10-year-old child were killed, but President Hamid Karzai escaped unhurt, according to an official and a statement from Karzai's office.

Afghan soldiers run to take up positions after shots were fired during a parade in Kabul on Sunday.

The attack also wounded more than 12 people, including a member of parliament, a Health Ministry official said.

The attack occurred at a Mujahedeen Victory Day ceremony, observing the 16th anniversary of Afghanistan mujahedeen fighters' overthrow of President Mohammad Najibullah's Soviet-backed regime.

Small arms fire erupted as a military band played the Afghan national anthem and as soldiers fired a 21-gun salute with artillery rounds.

The people standing did not react for several seconds, but security guards shielded Karzai and whisked him away from the reviewing stand. Other dignitaries quickly scrambled to safety. Watch military, crowd react to attack »

Karzai appeared on state-run television fewer than two hours later and called on citizens to remain calm.

The Health Ministry official said lawmaker Fazel Rahman Samkanai died from injuries sustained in the attack. A presidential statement said Nasir Ahmad Latifi, a council head of the Qezelbashan ethnic group, and a 10-year-old child were killed.

"Six of our Fedayeen martyrs entered to the stadium for the ceremony. They were heavily armed with mortars and machine guns. This was an organized attack. When the national anthem started they started the attack. Three were killed and three have survived," the statement said.

The Taliban also claimed its fighters got within 30 yards of the stand where Karzai and other dignitaries were standing. A diplomatic source said a mortar round landed near the stand.

Defense Ministry spokesman Zahir Azimi said the attackers were captured, but he did not say how many were in custody.

U.S. Ambassador William Wood and British Ambassador Sherard Cowper-Coles were in the stand, but were unhurt and later returned safely to their offices, spokesmen at their embassies said.

Uniformed U.S. military personnel also were in the stands and were not injured, U.S. Embassy spokesman Mark Stroh said.

United Nations Secretary-General Ban Ki-moon also condemned the attack. "This attack against the legitimate institutions of the Afghan state and the Afghan people is unacceptable," Ban said in a statement.

Afghanistan's state-run television station, which carried the ceremony live, captured the scene on camera.

As the fusillade became more intense, people turned to one another, some sat down and a few fell to the ground. Soon, people were scrambling from their seats while a stream of Afghan soldiers ran by, away from the sound of gunfire.

The live broadcast was interrupted about two minutes after the attack began.E-mail to a friend